The prior art reveals telescoping arms comprising pole handling grabbers or sheaves. In some cases these sheaves are convertible and can be secured to the end of one or other of the segments depending on whether the sheave is in use or not in use. One drawback of some of these prior art systems is that the pole handling sheaves are moveable even when not in use and can inadvertently come into contact with the other telescoping section when extended. On booms manufactured with heavy steel this is typically not a problem. However, on telescoping booms for use on utility poles and the like, the final telescoping sections are often manufactured from non-conducting composites which, although capable of supporting considerable weight, are easily damaged.